WebView长按保存图片；WebView不跳转到系统的浏览器；WebView加载显示进度条；WebView返回事件处理；

直接看代码即可，代码里面注释写的很清楚，这个类拉下来就能用；

写法和命名比较粗暴，但也简单易懂；

public class MainActivity extends AppCompatActivity {

    private final String TAG = MainActivity.this.getClass().getSimpleName();
    private WebView wv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        QbSdk.initX5Environment(this,null); //最好在application中
        getWindow().setFormat(PixelFormat.TRANSLUCENT);
        wv = findViewById(R.id.wv);
        final ProgressBar pb = findViewById(R.id.pb);
        wv.loadUrl("https://github.com/CuiChenbo/CcMall");
        wv.setWebViewClient(new WebViewClient(){
            @Override
            public boolean shouldOverrideUrlLoading(WebView webView, String url) {
                //重写此方法 可让webview不跳转到系统的浏览器
                webView.loadUrl(url);
                return super.shouldOverrideUrlLoading(webView, url);
            }
        });

        wv.setWebChromeClient(new WebChromeClient(){
            //WebView进度的回调监听
            @Override
            public void onProgressChanged(WebView webView, int i) {
                super.onProgressChanged(webView, i);
                if (i>=100){
                    pb.setProgress(100);
                    pb.setVisibility(View.GONE);
                }else {
                    pb.setProgress(i);
                }
            }

            //JS Alert的监听 可用来做和js（H5）的交互
            @Override
            public boolean onJsAlert(WebView webView, String s, String s1, JsResult jsResult) {
                return super.onJsAlert(webView, s, s1, jsResult);
            }
            //JsConfirm的监听
            @Override
            public boolean onJsConfirm(WebView webView, String s, String s1, JsResult jsResult) {
                return super.onJsConfirm(webView, s, s1, jsResult);
            }
           //JsPrompt 的监听  可用来做和js（H5）的交互
            @Override
            public boolean onJsPrompt(WebView webView, String s, String s1, String s2, JsPromptResult jsPromptResult) {
                return super.onJsPrompt(webView, s, s1, s2, jsPromptResult);
            }
        });
        //WebView长按的监听
        wv.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View view) {
               WebView.HitTestResult hitTestResult = wv.getHitTestResult();
              int type = hitTestResult.getType(); //获取触摸点的类型
              final String extra = hitTestResult.getExtra(); //获取触摸点的数据
                Log.i(TAG, "type:"+type+"____extra:"+extra);
                if (type == WebView.HitTestResult.IMAGE_TYPE||type == WebView.HitTestResult.SRC_IMAGE_ANCHOR_TYPE){
                    //说明触摸点的这个类型是图片类  去提示下载图片
                    AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.this);
                    dialog.setTitle("提示")
                    .setMessage("是否保存图片")
                            .setPositiveButton("保存", new DialogInterface.OnClickListener() {
                                @Override
                                public void onClick(DialogInterface dialogInterface, int i) {
                                   SeveImage(extra);
                                }
                            })
                            .setNegativeButton("取消",null)
                            .show();
                    return true;
                }else {
                    return false;
                }
            }
        });
    }
      //保存图片
    private void SeveImage(String extra) {
        DownloadManager downloadManager = (DownloadManager) getSystemService(DOWNLOAD_SERVICE);
        Uri uri = Uri.parse(extra);
        DownloadManager.Request request = new DownloadManager.Request(uri);
        //设置允许使用的网络类型，这里是移动网络和wifi都可以
        request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_MOBILE | DownloadManager.Request.NETWORK_WIFI);
        // 允许媒体扫描，根据下载的文件类型被加入相册、音乐等媒体库
        request.allowScanningByMediaScanner();
        //禁止发出通知，既后台下载，如果要使用这一句必须声明一个权限：android.permission.DOWNLOAD_WITHOUT_NOTIFICATION
        request.setShowRunningNotification(false);
        request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
        //不显示下载界面
        request.setVisibleInDownloadsUi(true);
        request.setDestinationInExternalFilesDir(MainActivity.this, Environment.DIRECTORY_PICTURES, System.currentTimeMillis() + ".jpg");
        //*设置下载后文件存放的位置,如果sdcard不可用，那么设置这个将报错，因此最好不设置如果sdcard可用，下载后的文件        在/mnt/sdcard/Android/data/packageName/files目录下面，如果sdcard不可用,设置了下面这个将报错，不设置，下载后的文件在/cache这个  目录下面*//*
        //request.setDestinationInExternalFilesDir(this, null, "tar.apk");
        long id = downloadManager.enqueue(request);
        IntentFilter intentFilter = new IntentFilter(DownloadManager.ACTION_DOWNLOAD_COMPLETE);
        DownloadMangerReceiver mDownloadMangerReceiver = new DownloadMangerReceiver();
        registerReceiver(mDownloadMangerReceiver, intentFilter);
    }

    //保存图片的监听
    class DownloadMangerReceiver extends BroadcastReceiver {
        private DownloadManager manager;

        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            manager =(DownloadManager)context.getSystemService(Context.DOWNLOAD_SERVICE);
            if (DownloadManager.ACTION_DOWNLOAD_COMPLETE.equals(action)) {
                Toast.makeText(context, "文件下载完成", Toast.LENGTH_SHORT).show();
                /*
                 * 获取下载完成对应的下载ID, 这里下载完成指的不是下载成功, 下载失败也算是下载完成,
                 * 所以接收到下载完成广播后, 还需要根据 id 手动查询对应下载请求的成功与失败.
                 */
                // 根据获取到的ID，使用上面第3步的方法查询是否下载成功
            }
        }
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        //改写物理返回键的逻辑
        if(keyCode== KeyEvent.KEYCODE_BACK) {
            if(wv.canGoBack()) {
                wv.goBack();//返回上一页面
                return true;
            } else {
                System.exit(0);//退出程序
            }
        }
        return super.onKeyDown(keyCode, event);
    }
}

layout布局文件也看一下:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
    android:layout_height="match_parent"
    android:layout_width="match_parent"
    >
    <ProgressBar
        android:id="@+id/pb"
        android:layout_width="match_parent"
        android:layout_height="2dp"
        android:max="100"
        android:background="@color/colorAccent"
       style="@style/Base.Widget.AppCompat.ProgressBar.Horizontal"
        />
    <com.tencent.smtt.sdk.WebView
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/wv"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context="com.ccb.pactera.x5webview.MainActivity">

    </com.tencent.smtt.sdk.WebView>
    </LinearLayout>

com.tencent.smtt.sdk.WebView是我用的X5WebView，有兴趣的可以去看一下：X5WebView